1. Field of the Invention
The present invention relates to a power unit for a saddle-ride vehicle. In the power unit, a transmission mechanism, which is disposed in the course of power transmission used for transmitting the torque of a crankshaft to a drive wheel, is installed in the crank case which rotatably supports the crankshaft and forms a part of an engine main body. Moreover, a shift actuator to drive and control the gear-shifting action of the transmission mechanism is disposed in the engine main body. The present invention, in particular, relates to an improved structure for disposing a shift actuator.
2. Description of Background Art
Japanese Unexamined Patent Application Publication No. Sho 63-125490 discloses a power unit to be mounted on a motorcycle. In the disclosed power unit, a shift actuator to drive and control the gear-shifting action of the transmission mechanism installed in a crankcase is disposed on the top surface of the crankcase.
A structure, such as one disclosed by Japanese Unexamined Patent Application Publication No. Sho 63-125490, in which the shift actuator is disposed on the top surface of the crankcase, imposes various constraints that lowers the degree of freedom in the layout for the functional parts of the motorcycle disposed above the crankcase, such as an intake system, an storage box, the battery, and a riding seat.
The present invention is made in view of the above-described circumstances.